RELATIVE HUMIDITY AS A FACTOR IN MICROCLIMATE AND PUBLIC HEALTH: A COMPARATIVE ANALYSIS OF UKRAINE AND ITALY
DOI:
https://doi.org/10.32782/health-2026.1.7Keywords:
relative humidity, absolute humidity, indoor air humidity, mould, risk factors, prevention, Ukraine, ItalyAbstract
Air humidity is one of the leading environmental factors determining the quality of the indoor environment and the health of the population. The aim of the study was to highlight and conduct a comparative analysis of the impact of different levels of indoor air humidity on the health of the population in Ukraine and Italy. A search, systematic review and meta-analysis of publications was conducted using the MEDLINE, Scopus®, ResearchGate, PubMed and Google Scholar scientific literature databases. The study summarises current scientific data on the impact of humidity on the functional state of the respiratory system, the spread of infectious agents and the formation of a safe microclimate in residential and public premises. It shows that deviations in relative humidity from the optimal range have a two-sided negative effect. A decrease in indicators below 30–40% during the heating season is associated with dehydration of the mucous membranes, impaired mucociliary clearance, decreased local immune defence, and an increased risk of transmission of respiratory viral infections. At the same time, increased humidity above 60–70% contributes to moisture condensation, mould growth and microbiological contamination of the air, which is associated with allergic reactions, exacerbation of chronic respiratory diseases and deterioration of the technical condition of building structures. It has been proven that the climatic characteristics of a region determine the nature of risks: in Ukraine, excessive dryness of the air during the heating season is a pressing problem, while countries with a Mediterranean climate more often experience chronically high humidity. A relative humidity range of 40–60% is considered optimal for maintaining human health. Maintaining this level requires systematic monitoring and the use of engineering and technical measures to regulate the microclimate. Humidity control should be considered an important component of the prevention of infectious and non-infectious respiratory diseases and a component of public health strategies
References
Joshi M., Goraya H., Joshi A., Bartter T. Climate change and respiratory diseases: a 2020 perspective. Current Opinion in Pulmonary Medicine. 2020. № 26 (2). P. 119–127. DOI: 10.1097/MCP.0000000000000656.
Seok J., Lee B., Yoon H. Y. Association between humidity and respiratory health: the 2016–2018 Korea National Health and Nutrition Examination Survey. Respiratory Research. 2024. № 25. P. 424. DOI: 10.1186/s12931-024-03054-z.
Aganovic A., Bi Y., Cao G., Kurnitski J., Wargocki P. Modeling the impact of indoor relative humidity on the infection risk of five respiratory airborne viruses. Scientific Reports. 2022. № 12 (1). P. 11481. DOI: 10.1038/s41598-022-15703-8.
Park J. E., Son W. S., Ryu Y., Choi S. B., Kwon O., Ahn I. Effects of temperature, humidity, and diurnal temperature range on influenza incidence in a temperate region. Influenza and Other Respiratory Viruses. 2020. № 14 (1). P. 11–18. DOI: 10.1111/irv.12682.
Verheyen C. A., Bourouiba L. Associations between indoor relative humidity and global COVID-19 outcomes. Journal of the Royal Society Interface. 2022. № 19 (196). P. 20210865. DOI: 10.1098/rsif.2021.0865.
Mecenas P., Bastos R. T. D. R. M., Vallinoto A. C. R., Normando D. Effects of temperature and humidity on the spread of COVID-19: a systematic review. PLoS ONE. 2020. № 15 (9). P. e0238339. DOI: 10.1371/journal.pone.0238339.
Mekhuri S., Quach S., Barakat C., Sun W., Nonoyama M. L. A cross-sectional survey on the effects of ambient temperature and humidity on health outcomes in individuals with chronic respiratory disease. Canadian Journal of Respiratory Therapy. 2023. № 59. P. 256–269.
Chen S., Liu C., Lin G., Hänninen O., Dong H., Xiong K. The role of absolute humidity in respiratory mortality in Guangzhou, a hot and wet city of South China. Environmental Health and Preventive Medicine. 2021. № 26 (1). P. 109. DOI: 10.1186/s12199-021-01030-3.
Bao H. R., Liu X. J., Tan E. L., Shu J., Dong J. Y., Li S. [Назва статті]. Beijing Da Xue Xue Bao Yi Xue Ban. 2020. № 52 (2). P. 308–316. DOI: 10.19723/j.issn.1671-167X.2020.02.019.
Mu Z., Chen P. L., Geng F. H. et al. Synergistic effects of temperature and humidity on the symptoms of COPD patients. International Journal of Biometeorology. 2017. № 61 (11). P. 1919–1925.DOI: 10.1007/s00484-017-1379-0.
Guarnieri G., Olivieri B., Senna G., Vianello A. Relative humidity and its impact on the immune system and infections. International Journal of Molecular Sciences. 2023. № 24 (11). P. 9456. DOI: 10.3390/ijms24119456.
Martazinova V. F., Horodetska N. S., Rybchenko L. S., Savchuk S. V., Hrebeniuk N. P., Tatarchuk O. H. Features of the current state of the temperature-humidity regime of Ukraine since the beginning of the XXI century under the influence of changes of large-scale atmospheric circulation. Meteorology. Hydrology. Environmental Monitoring. 2022. № 2 (2). P. 22–34. DOI: 10.15407/Meteorology2022.02.022.
Wolkoff P., Azuma K., Carrer P. Health, work performance, and risk of infection in office-like environments: the role of indoor temperature, air humidity, and ventilation. International Journal of Hygiene and Environmental Health. 2021. № 233. P. 113709. DOI: 10.1016/j.ijheh.2021.113709.
Robey A. J., Fierce L. Sensitivity of airborne transmission of enveloped viruses to seasonal variation in indoor relative humidity. International Communications in Heat and Mass Transfer. 2022. №130. P. 105747. DOI: 10.1016/j.icheatmasstransfer.2021.105747.
Božič A., Kanduč M. Relative humidity in droplet and airborne transmission of disease. Journal of Biological Physics. 2021. № 47. P. 1–29. DOI: 10.1007/s10867-020-09562-5.
World Health Organization. WHO Guidelines for Indoor Air Quality: Dampness and Mould. Copenhagen: WHO Regional Office for Europe, 2009.
Centers for Disease Control and Prevention. Mold and Health. Atlanta, GA: CDC, 2023.
American Society of Heating, Refrigerating and Air-Conditioning Engineers. ASHRAE Handbook – Fundamentals. Atlanta, GA: ASHRAE, 2021.
National Institute for Occupational Safety and Health. Criteria for a Recommended Standard: Occupational Exposure to Heat and Hot Environments. Cincinnati, OH: NIOSH, 2016.
Wolkoff P. Indoor air humidity revisited: impact on acute symptoms, work productivity, and risk of influenza and COVID-19 infection. International Journal of Hygiene and Environmental Health. 2024. № 256. P. 114313. DOI: 10.1016/j.ijheh.2023.114313.
Groot J., Nielsen E. T., Nielsen T. F., Andersen P. K., Pedersen M., Sigsgaard T., Loft S., Andersen A.-M. N., Keller A. Exposure to residential mold and dampness and the associations with respiratory tract infections and symptoms thereof in children in high income countries: a systematic review and meta-analyses of epidemiological studies. Paediatric Respiratory Reviews. 2023. № 48. P. 47–64. DOI: 10.1016/j.prrv.2023.06.003.
Norbäck D., Zock J. P., Plana E. et al. Building dampness and mold in European homes in relation to climate, building characteristics and socio-economic status: the European Community Respiratory Health Survey ECRHS II. Indoor Air. 2017. № 27 (5). P. 921–932. DOI: 10.1111/ina.12375.
Holzheimer R. G. Moisture damage and fungal contamination in buildings are a massive health threat – a surgeon's perspective. Central European Journal of Public Health. 2023. № 31 (1). P. 63–68. DOI: 10.21101/cejph.a7504.
Chong K. L., Ng C. S., Hori N., Yang R., Verzicco R., Lohse D. Extended lifetime of respiratory droplets in a turbulent vapor puff and its implications on airborne disease transmission. Physical Review Letters. 2021. № 126 (3). P. 034502. DOI:10.1103/PhysRevLett.126.034502.
Karamushka V., Boychenko S., Kuchma T., Zabarna O. Trends in the environmental conditions, climate change and human health in the southern region of Ukraine. Sustainability. 2022. № 14. P. 5664. DOI: 10.3390/su14095664.
Vyshnevskyi V. I. Climate change in Ukraine and its consequences. Journal of Landscape Ecology. 2025. № 18 (44).
Boychenko S., Holubka O., Karamushka V. About the influence of environmental conditions on the distribution of the SARS-CoV-19 virus in Ukraine. Geofizicheskiy Zhurnal. 2020. № 42 (5). P. 205–232. DOI: 10.24028/gzh.0203-3100.v42i5.2020.215085.
Rosina E., Esmaeilian Toussi H. Microclimate monitoring using multivariate analysis to identify surface moisture in historic masonry in Northern Italy. Applied Sciences. 2025. № 15 (15). P. 8542. DOI: 10.3390/app15158542.
Balboni E., Filippini T., Rothman K. J. et al. The influence of meteorological factors on COVID-19 spread in Italy during the first and second wave. Environmental Research. 2023. № 228. P. 115796. DOI: 10.1016/j.envres.2023.115796.
Alaniz A. J., Carvajal M. A., Carvajal J. G., Vergara P. M. Effects of air pollution and weather on the initial COVID-19 outbreaks in United States, Italy, Spain, and China: a comparative study. Risk Analysis. 2023. № 43 (1). P. 8–18.DOI: 10.1111/risa.14080.
Donzelli G., Biggeri A., Tobias A., Nottmeyer L. N., Sera F. Role of meteorological factors on SARS-CoV-2 infection incidence in Italy and Spain before the vaccination campaign: a multi-city time series study. Environmental Research. 2022.№ 211. P. 113134. DOI: 10.1016/j.envres.2022.113134.
